Connector plate

ABSTRACT

A connector plate, for connecting abutting wood members, formed of a sheet having numerous punched-out, narrow, elongated openings, with the punched-out material forming integral, identical mirror-image teeth at each end of their respective openings. The ends of the teeth are cut diagonally. The half of each tooth adjacent to the sheet is formed with a convex outer surface and V-shaped inner surface, and the free half of each tooth is formed generally flattened and gradually twisted around an axis perpendicular to the sheet so that its free diagonal edge is at a roughly 45* angle relative to the long edges of its respective opening.

United States Patent Jan. 11,1972

[21 Appl. No. [22] Filed [45] Patented [54] CONNECTOR PLATE 1 Claim, 7Drawing Figs.

[52] US. Cl 85/13 [51] Int. Cl ..143m 15/00 [50] Field of Search 85/13,49;

287/2092 CP; 52/D1G. 6

[5 6] References Cited UNITED STATES PATENTS 3/1966 Broder 5/1967Moehlenpah etal.

Primary Examiner-Marion Parsons, Jr. Atturney-Cu1len, Settle, Sloman &Cantor ABSTRACT: A connector plate, for connecting abutting woodmembers, formed of a sheet having numerous punchedout, narrow, elongatedopenings, with the punched-out material forming integral, identicalmirror-image teeth at each end of their respective openings. The ends ofthe teeth are cut diagonally. The half of each tooth adjacent to thesheet is formed with a convex outer surface and V-shaped inner surface,and the free half of each tooth is formed generally flattened andgradually twisted around an axis perpendicular to the sheet so that itsfree diagonal edge is at a roughly 45 angle relative to the long edgesofits respective opening.

PATENTEBJANI 1 ma 3.' s33,'454

INVENTORS JACK N. SCHMITT PAUL E. H0DGES,JR

, [MZ fi i ATTORN E Y3 CONNECTOR PLATE BACKGROUND OF INVENTION In theconstruction of houses and the like buildings, roof trusses and wallsections are frequently prefabricated at sites remote from theconstruction site and then brought to the construction site forassembly. In this type of construction, the wood members which are usedto fabricate a roof truss or wall section are frequently connectedtogether by means of connector plates.

Such plates have generally been formed of a sheet of stiff, relativelyrigid sheet metal having integral, struck-out teeth. In use, the woodmembers are aligned or abutted for assembly and then the connectorplates are laid over the joints and pressed into the wood so that theteeth pierce the wood and the plate serves as the connection meansbetween the individual wood members.

An example of this type of connector plate is disclosed in U.S. Pat. No.3,242,788 granted Mar. 29, 1966, to Broder.

Joints formed of such types of plates are generally strong; however,theteeth of the plates are subjected to relatively high shear loads andtherefore, tend to work free of the wood.

This is aggravated by the normal expansion and contraction and othermovement of wood fibers over periods of time with varying temperatureand weather conditions. Thus, it is desirable to provide such types ofplates with teeth which have the maximum resistance to shear loads andthe maximum ability to interlock with the wood fibres and remain sointerlocked despite varying conditions. The invention herein relates tosuch type of teeth constructions which considerably improve the plateutility and diminish the foregoing problems.

SUMMARY OF INVENTION The invention herein contemplates forming theintegral teeth struck out of a connector plate with an inner or lowerhalf having one, outer convex surface or face and opposite, inner faceformed in a V-shape, with the outer or extremity portion of the teethtwisted and flattened so as to gradually increase in angularity to apoint of about roughly 45 at its extreme edge relative to the initialangle of the tooth. This construction includes a sharp crease line whichforms a V-shaped surface, which crease line changes its direction nearthe outer edge of the tooth, to thereby provide a configuration which isunusually resistant to shear loads and which has a tendency to curl ortwist and interlock with the wood fibers, thereby substantially reducingany tendency of the teeth to become loose after a period of time andchanging weather conditions.

Thus, although the connector plate herein is superficially quite similarto that previously used, such as that illustrated in the above mentionedpatent, the small changes in the configuration of the teeth provide asubstantial difference in the results produced, namely a greatlystrengthened plate, more resistant to shear loads, and highly resistantto removal from or loosening relative to the wood members.

Further objects and advantages of this invention will become apparentupon reading the following description, of which the attached drawingsform a part.

DESCRIPTION OF DRAWINGS FIG. 1 is a plan view of a joint formed betweentwo wood members overlapped by the connector plate herein.

FIG. 2 is an enlarged perspective view of one pair of teeth.

FIG. 3 is a top, plan view of a pair of teeth, and

FIG. 4 is an elevational view taken in the direction of arrows 4-4 ofFIG. 3.

FIG. 5 is an elevational view of one tooth taken in the direction ofarrow 5-5 of FIG. 4, and

FIG. 6 is an elevational view of the opposite face of a tooth, taken inthe direction of arrow 66 of FIG. 4.

FIG. 7 is a fragmentary, cross-sectional view taken in the direction ofarrow 77 of FIG. 6.

DETAILED DESCRIPTION FIG. 1 illustrates a connector plate 10 formed of astiff, rigid, sheet metal, used to interconnect a pair of abutting woodmembers 11 and 12 to form a joint. The wood members may form part of atruss assembly or wall section or the like.

The plate is provided with rows of punched-out openings I3, which arenarrow and elongated and aligned as illustrated in FIG. I. The materialpunched out of each opening is split into two opposite tooth-formingportions which provide integral teeth 14 and 15 at the opposite ends ofeach opening (see FIG. 2). The teeth are identical, but mirror images.

The invention herein relates to the configuration of the teeth whichproduces the result of increased shear strength and increasedinterlocking with the wood fibers.

As illustrated in the drawings, each tooth has its upper edge out alonga diagonal to form an upper end 17 which provides a long side edge 18and a short side edge 19 on the tooth.

Each tooth is divided along its length into a lower or inner halfportion 20 and an upper or outer half portion 21. The outer face 22 ofeach lower portion is formed convex or outwardly bowed. However theinner face of each tooth, that is the face of the tooth facing towardsits opposite tooth, is provided with a sharp crease 23 extending abouthalfway up along the length of the tooth so that the inner face isformed in a V- shape in cross section. The crease, as seen in FIG. 2,extends upwardly further at an angle so that its extension 24 intersectsthe short side edge 19 just below the tip or extremity of the short sideedge 19.

The upper half portion on each tooth is twisted around an axis which isperpendicular to the sheet and is generally flattened, between thecrease extension 24 and the long leg 18, so that the outer edges 17 arearranged at roughly an angle of 45 relative to the long edges of theiropenings 13 (see FIG. 3). The tips 25 of each pair of teeth are thuscloser towards each other than are the tips or extremities of theshorter legs 19 on each pair of teeth.

In the twisting, the tips 26 of the shorter legs, upwardly of the crease24, tends to move slightly rearwardly relative to the edge 19 thusforming a slight bow 27 below androughly parallel to the edge 17 of eachtooth.

In operation, the wood members to be assembled are abutted in assemblyposition and a plate is laid over them with the teeth facing downwardlytoward the wood members. Then the plate is pressed toward the wood sothat its teeth pierce and embed within the wood. During this step, thewood fibers tend to twist and wrap around each of the teeth andinterlock therewith in a permanent fashion with the fibers being undersome tension so that they tend not to loosen despite expansion andcontraction of the wood in varying weather conditions.

Having fully described an upper tooth embodiment of this invention, wenow claim:

1. In a connector plate, for connecting together abutting pieces ofwood, and comprising a thin, rigid, metal sheet having a number ofidentical punched openings formed therein, each opening being narrow andelongated, with the sheet material bent upward from each such opening toform a pair of identical but mirror image teeth, each integral with oneend of said opening and extending perpendicular to said sheet, with eachtooth having an innerface, facing towards the opposite tooth of itspair, and an opposite outer face, the improvement comprising:

each tooth having its free end formed at an acute angle relative to thesheet, with one side edge of the tooth being longer than the other;

each tooth being divided along its length into two integral halfportions, namely an lower half portion located adjacent to the sheet andan upper half portion located adjacent its free end, with the lowerportion having its outer face formed convex in cross section; butextending perpendicularly to the sheet;

crease line formed therein approximately midway between said two sideedges of the tooth. to form said V shape, with the crease extendingabout halfway towards said tooths free end from the tooths integral endand the crease then continuing at an angle to intersect with the toothsshorter side edge near the tip of the shorter side edge, and the tooth'sarea between the crease and the shorter side edge being untwisted.

I I l 1! l

1. In a connector plate, for connecting together abutting pieces ofwood, and comprising a thin, rigid, metal sheet having a number ofidentical punched openings formed therein, each opening being narrow andelongated, with the sheet material bent upward from each such opening toform a pair of identical but mirror image teeth, each integral with oneend of said opening and extending perpendicular to said sheet, with eachtooth having an innerface, facing towards the opposite tooth of itspair, and an opposite outer face, the improvement comprising: each toothhaving its free end formed at an acute angle relative to the sheet, withone side edge of the tooth being longer than the other; each tooth beingdivided along its length into two integral half portions, namely anlower half portion located adjacent to the sheet and an upper halfportion located adjacent its free end, with the lower portion having itsouter face formed convex in cross section; but extending perpendicularlyto the sheet; and the upper portion being generally flattened androtated about an axis perpendicular to the sheet to gradually increasein angularity relative to the lower portion, to the point where the freeend of the tooth is arranged at a roughly 45* angle relative to the longedges of its respective opening, and the free tip of the long edge islocated closer towards the opposite tooth than is the tip of the shorteredge; with such shorter edge being bowed rearwardly near its tip; saidlower portion of the tooth inner face having a sharp crease line formedtherein approximately midway between said two side edges of the tooth,to form said V-shape, with the crease extending about halfway towardssaid tooth''s free end from the tooth''s integral end and the creasethen continuing at an angle to intersect with the tooth''s shorter sideedge near the tip of the shorter side edge, and the tooth''s areabetween the crease and the shorter side edge being untwisted.